This invention relates in general to vehicles and, in particular, to a vehicle suspension.
More specifically, but without restriction to the particular use which is shown and described, this invention relates to a resilient rear suspension in the rear-axle-to frame joint of a vehicle to attenuate the structural borne noise transmitted to the operator's compartment from the drive gears. The resillient rear suspension of the invention further provides vertical, fore and aft, and lateral stability to improve operation of the vehicle.
In the operation of construction and industrial machinery, such as, for example, conventional road graders, known equipment has subjected the operator to high levels of noise which is transmitted to a large extent from the drive gears of the vehicle to the operator's compartment. Maximum noise occurs generally when the machine is driven or roaded in high gear, often subjecting the operator to discomfort and potential interefrence with his effective operation of the vehicle. Federal regulations now specify stringent exposure levels of noise which are acceptable in the operator's compartment during operation of construction equipment. In the prior art a conventional grader employes a rear axle which is rigidly mounted to the vehicle frame through trunnions that transmit noise from the drive gears to the operator's compartment. A high level of noise transmission from the drive gears to the frame in prior graders is attributable to the rear suspension employing a rigid axle mount with metal to metal contact. This conventional suspension technique thus transmits noise to the operator's cab without significant isolation.